Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

<image>

In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
int arr[101][101];
int out[101][101];
int main() {
  int n, m;
  cin >> n >> m;
  vector<int> row;
  vector<int> col;
  for (int i = 1; i <= n; i++) {
    int mn = INFINITY;
    for (int j = 1; j <= m; j++) {
      cin >> arr[i][j];
      mn = min(mn, arr[i][j]);
    }
    for (int j = 1; j <= m; j++) {
      out[i][j] = mn;
    }
    row.push_back(mn);
  }
  int flag = 0;
  for (int i = 1; i <= m; i++) {
    if (arr[1][i] == out[1][i]) {
      col.push_back(0);
    } else {
      int xx = arr[1][i] - out[1][i];
      for (int j = 1; j <= n; j++) {
        out[j][i] += xx;
      }
      col.push_back(xx);
    }
  }
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= m; j++) {
      if (arr[i][j] != out[i][j]) {
        flag = 1;
        break;
      }
    }
    if (flag == 1) break;
  }
  if (flag == 1)
    cout << "-1" << endl;
  else {
    vector<int> row1;
    vector<int> col1;
    int cnt1 = 0;
    for (int i = 1; i <= m; i++) {
      int mn = INFINITY;
      for (int j = 1; j <= n; j++) {
        mn = min(mn, arr[j][i]);
      }
      for (int j = 1; j <= n; j++) {
        out[j][i] = mn;
      }
      col1.push_back(mn);
      cnt1 += mn;
    }
    for (int i = 1; i <= n; i++) {
      if (out[i][1] == arr[i][1]) {
        row1.push_back(0);
      } else {
        int xx = arr[i][1] - out[i][1];
        for (int j = 1; j <= m; j++) {
          out[i][j] += xx;
        }
        row1.push_back(xx);
        cnt1 += xx;
      }
    }
    int cnt = 0;
    for (int i = 0; i < row.size(); i++) {
      cnt += row[i];
    }
    for (int i = 0; i < col.size(); i++) {
      cnt += col[i];
    }
    if (cnt < cnt1) {
      cout << cnt << endl;
      for (int i = 0; i < row.size(); i++) {
        for (int j = 0; j < row[i]; j++) {
          cout << "row " << i + 1 << endl;
        }
      }
      for (int i = 0; i < col.size(); i++) {
        for (int j = 0; j < col[i]; j++) {
          cout << "col " << i + 1 << endl;
        }
      }
    } else {
      cout << cnt1 << endl;
      for (int i = 0; i < row1.size(); i++) {
        for (int j = 0; j < row1[i]; j++) {
          cout << "row " << i + 1 << endl;
        }
      }
      for (int i = 0; i < col1.size(); i++) {
        for (int j = 0; j < col1[i]; j++) {
          cout << "col " << i + 1 << endl;
        }
      }
    }
  }
}